• Journal of Dairy Science and Biotechnology
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• v.37 no.3
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• pp.206-212
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• 2019

This study was conducted to investigate the effect of cryoprotectants on the storage stability of Lactobacillus fermentum SK152, which was isolated as a probiotic candidate. Solutions of 10% glucose, trehalose, dextrin, and skim milk powder were used as cryoprotectants. The survival rates of L. fermentum SK152 after freeze-drying were 5.6% (dextrin), 2.2% (skim milk powder), 1.7% (glucose), and 1.5% (trehalose), suggesting that dextrin was most effective at minimizing the cell death of L. fermentum SK152 by lyophilization. The survival rates of L. fermentum SK152 stored at 4℃ ranged from 37% (dextrin)-90% (skim milk powder) after 8 weeks, while those at 20℃ ranged from 4% (dextrin)-12% (skim milk powder) after 7 weeks, indicating that skim milk powder was the best at minimizing the cell death of L. fermentum SK152 during storage, irrespective of storage temperature, among the cryoprotectants used.

• Journal of Service Research and Studies
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• v.5 no.1
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• pp.91-103
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• 2015

We examine the information transmission between the KT Spot and the KT Futures Index, the SK Telecom Spot and the SK Telecom Futures Index, based on the returns data offered by the Korea Exchange. The data includes daily return data from 1 January 2012 to 31 December 2014. Utilizing a dynamic analytical tool-the VAR model, Granger Causality test, Impulse Response Function and Variance Decomposition have been implemented. The results of the analysis are as follows. Firstly, results of Granger Causality test suggests the existence of mutual causality the KT Futures Index and the SK Telecom Futures Index precede and have explanatory power the KT Spot and the SK Telecom Spot However the results also identified a greater causality and explanatory power of the KT Spot and the SK Telecom Spot over the KT Futures Index and the SK Telecom Futures Index. Secondly, the results of impulse response function suggest that the KT Futures Index show immediate response to the KT Spot and are influenced by till time 4. From time 2, the impact gradually disappears. Also the SKT Futures Index show immediate response to the SKT Spot and are influenced by till time 4. From time 2, the impact gradually disappears. Lastly, the variance decomposition analysis shows that the changes of return of the KT Spot and SKT Spot are dependent on those of the KT Futures Index and the SK Telecom Futures Index. This implies that returns on the KT Spot and SKT Spot have a significant influence over returns on the KT Futures Index and the SK Telecom Futures Index. It contributes to the understanding of market price formation function through analysis of detached the KT Spot and the KT Futures Index, the SK Telecom Spot and the SK Telecom Futures Index.

• 월간 기계설비
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• s.304
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• pp.76-85
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• 2015

최근들어 전력 소비량이 크게 늘어나자 정부는 원활한 전력 공급을 위해 제5차 및 제6차 전력수급계획을 세우고 2022년까지 발전소 건설을 목표로 함에 따라 전국 곳곳에서 발전소 건설공사가 한창이다. 이 중 PMP(주)가 경기도 파주시에 건설 중인 장문 천연가스발전소는 1,820MW 규모의 천연가스복합화력 발전소다. 지난 6월 1일 착공에 들어가 오는 2017년 3월 말까지 완공될 예정이다. 장문 천연가스발전소는 제5차 전력 수급기본계획에 따른 국가 기간산업으로 수도권 북부지역에 전력을 충분히 공급함은 물론 주변지역의 대규모 산업단지와 기업체에도 공급 가능성이 큰 대규모 발전소다. 또한 SK그룹은 풍부한 발전소 운영경험을 기반으로 고효율 발전설비를 갖춤으로써 전력시장에서 높은 경쟁력을 확보할 수 있을 것으로 기대하고 있다. (주)세일엔지니어링(대표 오세현)은 장문 현장에서 #11, #12의 2기 HRSG(Heat Recovery steam Generator) 설치공사를 SK건설(현장소장 이원기)로부터 하도급 받아 시공하고 있다. 본지는 2017년 3월 말까지의 완공을 목표로 무결점 시공에 올인하고 있는 (주)세일엔지니어링의 주남식 현장소장을 만났다.

• Journal of Applied Reliability
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• v.18 no.1
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• pp.33-39
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• 2018

Purpose: Accelerated degradation tests can be effective in assessing product reliability when degradation leading to failure can be observed. This article proposes an accelerated degradation test model for highly reliable solid state drives (SSDs). Methods: We suggest a nonlinear mixed-effects (NLME) model to degradation data for SSDs. A Monte Carlo simulation is used to estimate lifetime distribution in accelerated degradation testing data. This simulation is performed by generating random samples from the assumed NLME model. Conclusion: We apply the proposed method to degradation data collected from SSDs. The derived power model is shown to be much better at fitting the degradation data than other existing models. Finally, the Monte Carlo simulation based on the NLME model provides reasonable results in lifetime estimation.

• Journal of Ginseng Research
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• v.23 no.3 s.55
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• pp.190-197
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• 1999

In this study, the molecular mechanism of the growth inhibitory effect of panaxynol was investigated in a human malignant melanoma cell line, SK-MEL-l. In the cell cycle analysis, panaxynol arrested cell cycle progression of SK-MEL-I at the G1 phase. Immunoblot analysis demonstrated that panaxynol increased $p21^{WAF1}$ and decreased cdc2 expression. Protein levels of pl6, p27, E2F-1, Rb, and p53 were not changed. Thus, the changes in expression levels of $p21^{WAF1}$ and cdc2 apparently mediate the cell cycle arrest caused by panaxynol. In addition, cycloheximide (CHX) partially reversed the growth inhibition by panaxynol, which suggested that new protein synthesis was required. On the other hand, LLnL, a proteasome inhibitor, increased antiproliferative effect of panaxynol. This may be due to stabilization of the protein(s) responsible for the growth inhibition such as $p21^{WAF1}$. In summary, these results demonstrate that panaxynol inhibits proliferation of SK-MEL-I by inducing cell cycle arrest at the G1 phase and the inhibitory effect is mediated by the increased level of $p21^{WAF1}$ as well as decreased cdc2 expression.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.4 no.1
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• pp.3-10
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• 1997

The purpose of this research was to complete basic study about standardization of corrugated fibreboard containers for apples. Various corrugated fibreboard containers are studied and the results are shown below. 1. WLK, SK, and KA are usually used for outer liner boards, S and $K_2$ are for medium or inner liner boards. 2. According to the study, about twenty different liner compositions are currently used for apple packaging. However, for the containers with white liner board, the liner composition is WLK210/M200/S120/$M200/K_{2}200$, for the containers with colored liner board, SK180/M200/S120/$M200/K_{2}200$ are mostly used. 3. Sixteen percents of cost saving are expected when subsitute white outer liner boards by those of colored.

• Analytical Science and Technology
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• v.18 no.2
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• pp.104-111
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• 2005

Several solvents were used to fractionate an extract obtained from the chapped root bark of Ulmus davidiana Planchon. The each fractionary part was condensed under reduced pressure and then examined to investigate the inhibitory effect on MMPs by modified gelatin zymography, where EA fraction showed the inhibition effect on the activity of MMPs. A compound showing inhibition effect on the MMPs was isolated and purified from EA fraction. Under IR, $^1H$- and $^{13}C$- NMR analyses it is very close to a catethin. This substance showed 48% inhibition effect on measurement of MMP-9 activity at 5 mM and 43% at 10 mM. To verify the effect of this substance on cells, human hepatoma, SK-Hep-1 cells as a cancer model, and Chang liver cells as a normal model were selected. MTT assay was performed to examine the cell viability by treatment of $1{\mu}L/mL$ of the purified substance on cells. The purified substance showed negligible toxicity on human liver cell line.

• The Journal of Korean Medicine
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• v.25 no.2
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• pp.138-150
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• 2004

Objectives : Alzheimer's disease (AD) is a geriatric dementia that is widespread in old age. In the near future AD will be the biggest problem in public health service. Although a variety of oriental prescriptions, including Sesim-tang, have been traditionally utilized for the treatment of AD, their pharmacological effects and action mechanisms have not yet been fully elucidated. The present study investigated the effects of Sesim-tang on apoptotic cell death induced by CT105 (carboxy terminal 105 amino acid peptide fragment of APP) overexpression in SK-N-SH neuroblastoma cell lines. Methods: We studied the regenerative and inhibitory effects on Alzheimer's disease in CT105-induced SK-N-SH cell lines by Sesim-tang water extract. We examined for cell morphological pattern, DNA fragmentation, LDH activity assay, zymography assay, and immunohistochemistric analysis. Additionally, we investigated the association between the CT105 and neurite degeneration caused by CT105-induced apoptotic response in neurone cells. Results: Findings from our experiments have shown that Sesim-tang inhibits the synthesis or activities of CT105, which has neurotoxicities and apoptotic activities in the cell line. In addition, pretreatment with Sesim-tang ($>50\mu\textrm{g}/ml$ for 12 hours) partially prevented CT105-induced cytotoxicity in SK-N-SH cell lines. SK-N-SH cell lines overexpressed with CT105 exhibited remarkable apoptotic cell damage. Based on morphological observations by phase-contrast microscope and LDH activity measurements in the culture media, the CT105-induced cell death was significantly inhibited by Sesim-tang water extract. Sesim-tang was found to reduce the expression of APP and caspase-3 induced by CT105 in SK-N-SH cell lines and in rat hippocampus. Conclusions: As the result of this study, in the Sesim-tang group, apoptosis in the nervous system is inhibited, the repair against the degeneration of SK-N-SH cell lines by CT105 expression is promoted. Hence, Sesim-tang may be beneficial for the treatment of AD.

• Journal of Korea Water Resources Association
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• v.48 no.4
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• pp.245-255
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• 2015

This study used high density network of integrated meteorological sensor, which are operated by SK Planet, with KMA weather stations to estimate the quantitative precipitation field in Seoul area. We introduced SK Planet network and analyzed quality of the observed data for 3 months data from 1 July to 30 September 2013. As the quality analysis result, we checked most SK Planet stations observed similar with previous KMA stations. We developed the real-time quality check and adjustment method to reduce the error effect for hydrological application by missing and outlier value and we confirmed the developed method can be corrected the missing and outlier value. Through this method, we used the 190 stations(KMA 34 stations, SK Planet 156 stations) that missing ratio is less than 20% and the effect of the outlier was the smallest for quantitative precipitation estimation. Moreover, we evaluated reproducibility of rainfall field high density rain gauge network has $3km^2$/gauge. As the result, the spatial relative frequency of rainfall field using SK Planet and KMA stations is similar with radar rainfall field. And, it supplement the blank of KMA observation network. Especially, through this research we will take advantage of the density of the network to estimate rainfall field which can be considered as a very good approximation of the true value.

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.688-693
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• 2002

The anticarcinogenic effects of various food components have received much attention in recent years. However mechanism of anticarcinogens in food materials on cancer cells have rarely been investigated. This study was performed to investigate the effects on the cytotoxicity and quinone reductase (QR) activity of Allium tuberusum (AT) on the human cancer cells. The six partition layers which are methanol (ATM), hexane (ATMH), ethylether (ATMEE), ethylacetate (ATMEA), butaonl (ATMB) and aqueous (ATMA) of Allium tuberusum were screened for their cytotoxic effects on HepG2, MCF-7, HeLa and SK-N-MC cells by the MTT assay. Among the six partition layers, ATMEE had the strongest cytotoxic effect at concentration of $150\;{\mu}g/mL$ which resulted over 95% on HepG2, HeLa, MCF-7 and SK-N-MC cell lines. The ATMEA also showed significant cytotoxic effect on HepG2 and SK-N-MC cell lines. The ATMB showed the highest induction activity of QR on HepG2 cells among the other partition layers. QR activity of HepG2 cells, grown in the presence of ATMB at the concentration of $50\;{\mu}g/mL$, was increased by 3.9 times, compared to the control value of 1.0. Based on these results, the ATMEE and ATMB may have potentially anticarcinogenic and chemopreventive activities.